The educational extension program of the Illinois State Geological Survey
Series: Illinois State Geological Survey. Circular -- no. 142; Circular (Illinois State Geological Survey) -- no. 142.; Circular (Illinois State Geological Survey) -- 142.
Published: 1948
Place of publication: Urbana
Language: eng
Number of pages: 142
Subjects: Study and teaching; Illinois State Geological Survey; Geology
Notes: Cover title.

"Reprinted from School science and mathematics, vol. 48, no. 2, pp. 139-142, February, 1948."